SEBU8337 27
Operation Section
Features and Controls
Failure of the C
oolant Temperature
Sensor
The ECM w ill de
tect a failure of the coolant
temperature sensor. The diagnostic lamp will
warn the operator about the status of the coolant
temperature
sensor. A failure of the coolant
temperature sensor will cause a shutdown of the
engine. The faulty sensor should be replaced. Refer
to Disassemb
ly and Assembly Manual, “Coolant
Temperature Sensor - Remove and Install”.
Intake Manifold Pressure Sensor 2
The intake ma
nifold pressure sensor measures boost
pressure in the intake manifold. A signal is sent to the
ECM. A failure of the inlet manifold pressure sensor
will limit t
he power of the engine.
Intake Mani
fold Air Temperature
Sensor 3
The Intake manifold air temperature sensor measures
the intake air temperature. A signal is sent to the
ECM. The in
take manifold air temperature sensor is
also used by the ECM to determine initiation of the
Cold Start Strategy.
Atmospheric Pressure Sensor 4
All the output signals from the pressure sensors are
matched to the output signal of the atmospheric
pressure
sensor during calibration. The signal from
the atmospheric pressure sensor is used by the ECM
in order to determine the operating altitude of the
engine. I
f necessary, the ECM can derate the engine.
Secondar
y Speed/Timing Sensor 5
The signal from the secondary speed/timing sensor
is used b
y the ECM on engine start-up in order to
determine the stroke that the pistons are on. The
secondary speed/timing sensor may be used by the
ECM in or
der to operate the engine if the primary
speed/timing sensor is faulty.
In order
to check the correct operation of the sensor,
refer to Troubleshooting, “Engine speed/Timing
sensor-Test”.
Engine Oil Pressure Sensor 6
The engine oil pressure sensor is an absolute
pressure sensor that measures the engine oil
pressu
re in the main oil gallery. The engine oil
pressure sensor detects engine oil pressure for
diagnostic purposes. The engine oil pressure sensor
sends
a signal to the ECM .
Low Oil Pressur
e Warning
The setpoint for the low pressure warning is
dependent upo
n the engine speed. The fault will be
active and logged only if the engine has been running
for more than 8 seconds.
Low Oil Pressure
The very low oi
l pressure setpoint is dependent upon
the engine speed. If very low oil pressure is detected,
the ECM will stop the engine immediately unless
Critical Eve
nts Override is active.
Failure of the Engine Oil Pressure Sensor
The ECM will detect failure of the engine oil pressure
sensor. The diagnostic lamp warns the user about the
status of the
engine oil pressure sensor. The engine
oil pressure related strategies will be disabled in the
event of a failure of the engine oil pressure sensor.
Afailureof
the engine oil pressure sensor will cause
a shutdown of the engine. The faulty sensor should
be replaced. Refer to Disassembly and assembly
Manual, “E
ngine Oil Pressure Sensor - Remove and
Install”.
Fuel Temperature Sensor 7
The fuel te
mperature sensor monitors the fuel
temperature. The signal from the sensor allows
the ECM to compensate for changes in the fuel
temperatu
re by adjusting the fuel rate for constant
power.
Primary Speed/Timing Sensor 8
If the ECM
does not receive a signal from the primary
speed/timing sensor , the “DIAGNOSTIC” lamp will
indicate a diagnostic fault code which will be logged
in the ECM
memory.
If the ECM does not receive a signal from the primary
speed/t
iming sensor (9), the ECM will read the signal
from the secondary speed/timing sensor (2). The
ECM continually checks in order to determine if
there is
a signal from both sensors. If either sensor
fails, the faulty sensor should be replaced. Refer to
Disassembly and Assembly Manual, “Crankshaft
Positi
on Sensor - Remove and Install” or refer to
Disassembly and Assembly Manual, “Camshaft
Position Sensor - Remove and Install”.
Intermittent failure of the sensors will cause erratic
engine control.
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